As a technology for accurately measuring a location on the ground, a global positioning system (GPS) technology using an artificial satellite has been prevalently used.
In recent years, the GPS technology is widely propagated among the people and thus, has been applied for car navigation, mobile communication terminals, climbing GPS equipment, etc. A location based service industry based on the GPS technology has been rapidly grown. As an alternative plan for GPS failure in a GPS shadow area in which a satellite signal is weakly sensed, various types of network based positioning systems have been developed.
Examples of the network based positioning technologies may include an MS-Assisted method in which a terminal receives necessary information and then a location server calculates an end location of the terminal, an MS-based method in which a terminal receives information necessary for positioning from the location server and then, performs the last positioning, and an autonomous method in which a terminal performs positioning without the help of a location server.
The positioning of the MS-based method or the autonomous method is the most recently commercialized technologies and the existing LBS service mainly uses the MS-assisted based positioning. Consequently, the terminal location information provision by the existing LBS service follows a location server based call flow.
The aforementioned location server based location information providing service is suitable for a disposable location inquiry service such as a my location inquiry or a friend search, but is not suitable for a periodic location inquiry service.
Recently, a terminal based service such as a car navigation system (CNS) or a personal navigation system (PNS) due to the introduction and commercialization of positioning technologies such as the MS-based method or the autonomous method has been developed. The terminal based location providing service is a service in which the terminal periodically measures its own location and use the measured location, which is an impossible service in the existing location server based location tracking system.
However, even in the case of the service, the terminal uses only its own location. Therefore, when intending to periodically inquire and use a location of another person, there is still a need to use the location server based location tracking system, which leads to a problem in greatly increasing the load of the server or the network and limiting the function and quality of service.
The terminal based location tracking service inquiring the location of another person is implemented based on a method of acquiring location information on a tracked terminal by driving a period management and positioning system in an existing location based service platform (LBSP) and providing the acquired location information to a tracking terminal. In the method, when the tracked terminal performs the positioning of the MS-based method and the terminal performs the period management, the location server simply serves to receive the location information calculated in the tracked terminal from the tracked terminal to transmit the calculated location information to a tracking terminal and thus, the unnecessary communication between the terminal and the location server is frequent and the terminal needs to manage the period management, or the like and thus, the unnecessary load of the server and the network is increased.
Further, since the location service is essential and all the data are processed in the location server, the high-performance equipment is required.
In addition, the related art has a problem in that the personal information such as the location information of the user, or the like, is published to other persons and location information providers.
Moreover, the related art as the location tracking system of a user based protocol has not proposed a preferred processing method for a case in which the terminal user does not answer a location tracking acknowledgement request and thus, has a problem in performing the location tracking procedure.